<!DOCTYPE html>
<html>
<head>
<title>Try jQuery Online</title>
<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script>
$(document).ready(function() {
   $("em").addClass("selected");
   $("#myid").addClass("highlight");
});

</script>
<style>
.selected { 
    color:red; 
}
.highlight { 
    background:yellow; 
}
</style>
</head>
<body>
<em title="Bold and Brave">This is first paragraph.</em>
<p id="myid">This is second paragraph.</p>
</body>
</html>
